Allison 1000 Transmission Stage 1 500HP Max (01-10)

$12,455.40

Allison 1000 Transmission Stage 1 500HP Max (01-10) — built and tested by Randy’s Transmissions for dependable towing and daily driving. Imported to order and backed by the team at Willys Workshop.

Imported to order — through our workshopWe bring this in from our supplier and receive it at our workshop first. From there we can build, tune or fit it for you — or ship it straight to you or your mechanic. Freight and any workshop work are quoted on enquiry.

Available to order

SKU: WEBKIT.P17 Categories: , Brand:
Workshop Fitment & Tuning
Built & Calibrated to Spec
Up to 24 Month Warranty

Free Shipping

Easy returns within 14 days

12 month warranty

Description

Stage 1 Allison 1000 Transmission for Chevy & GMC Duramax Pickups

When it comes to towing heavy loads or adding a bit of extra power to your Chevy or GMC Duramax, the Allison 1000 transmission is a trusted workhorse. Randy’s Stage 1 Allison 1000 upgrade takes this already robust transmission and refines it for even better performance, durability, and reliability, making it the ultimate choice for any truck pushing up to 500 horsepower.

The Perfect Transmission for Towing and Mild Performance Enhancements

Designed for the truck owner who needs their vehicle to handle the daily grind, this Stage 1 Allison 1000 transmission ensures your Duramax has the reliable holding power needed to handle up to 500 HP. Whether you’re hauling a heavy trailer up a steep mountain pass or looking for a smoother, more efficient power delivery for your day-to-day drives, this transmission upgrade is built to deliver.

Key Features & Components

Our Stage 1 Allison 1000 transmission kit is loaded with high-quality components designed to maximize performance and longevity. Here’s what you can expect:

  • Raybestos or ALTO G3 C-3 and C-4 Packs with Additional Clutch Count: These clutches provide superior holding power, ensuring your transmission can handle the extra torque without slipping, even under heavy loads.
  • Randy’s Billet Torque Converter: Our built-in-house billet torque converter that enhances lock-up efficiency and torque transfer for smoother acceleration and increased durability.
  • Modified Lock-Up Valve: Optimized to enhance performance in towing and daily driving, ensuring better engagement and torque transfer.
  • Transgo Trim Valves: Improves fluid pressure regulation, reducing internal wear and extending the life of your transmission.
  • New Bonded Pistons: Improves overall durability and reliability, ensuring smooth shifting and efficient power transfer.
  • Raybestos or ALTO G3 C-1 and C-2 Clutches: High-performance clutches that provide superior durability and heat resistance.
  • New Bearings:We replace all the bearings to guarantee a smooth, reliable operation, reducing friction and wear.

Why Choose Randy’s Stage 1 Allison 1000?

This transmission is designed for those who need their truck to hold a bit more power. With improved clutch packs and billet components, our Stage 1 transmission is engineered to handle up to 500 horsepower, keeping your Duramax running strong for years to come.

Built for Durability, Tested for Excellence

Every transmission we build is tested rigorously, ensuring it can stand up to the demands of real-world use. Whether you’re towing, hauling, or just driving around town, Randy’s Stage 1 Allison 1000 transmission is built to go the distance.

Buy Now, Pay Later

We know that upgrading your transmission is a big investment and paying all at once can be tough. That’s why we’ve teamed up with Affirm to make it easier for you. With our financing options, you can enjoy the benefits of a top-quality transmission without the stress of a hefty upfront payment. Available exclusively online, just choose Affirm at checkout and spread your payments out over time. Get the performance you need today, and pay at a pace that fits your budget.

2 Year / Unlimited Mile Warranty

When you choose Randy’s Stage 1 Allison Transmission, you’re backed by confidence and reliability. We stand behind our product with a 2-year, unlimited mile warranty, ensuring your transmission performs at its best—no matter how hard you push it. Whether you’re towing heavy loads or running down the road, rest easy knowing that our warranty has you covered. We’re committed to providing long-term durability and peace of mind with every build.

At Randy’s, we believe in long-term relationships, not just one-time transactions. That’s why our Refresh Program is here to support you even after your warranty expires. When your transmission needs a little TLC, we’ll give it a thorough rebuild at a fraction of the cost of a new unit. It’s our way of showing our commitment to your vehicle’s performance and your satisfaction. Please remember, this program is available only to the original owner and is non-transferable. With Randy’s, you’re not just buying a transmission; you’re investing in lasting peace of mind and continued excellence on the road.

Years of Experience, Proven Results

Imported to Order — Through Our Workshop

  • Brought in from our supplier and received at our Sunshine Coast workshop first.
  • From there we can build, tune or fit it for you, or ship it on to you or your mechanic.
  • Freight and any workshop work are quoted on enquiry — international freight, customs and delivery vary by item and destination.
  • Typical lead time is confirmed at the time of order.

Get a freight + build quote: call (07) 5619 7869 or email sales@willysworkshop.com.au.

Additional information

Weight 115 kg
Dimensions 75 × 60 × 55 cm

Randy's Transmissions — Limited Warranty

Randy's Transmissions warrants all reman transmissions, torque converters and serviced components per the published Randy's Limited Warranty:

  • 12 months / unlimited km on reman transmissions (street use)
  • Lifetime on Randy's hard parts (gears, shafts) where stated
  • Claims processed via Randy's Warranty Claims & Support form
  • Original proof of purchase required
  • Competition / off-road use excluded unless specifically stated

Fitment by Willys Workshop can be arranged in-house at our Oxley or Warana locations — workshop fitment receipts count toward warranty claim documentation.

Read the full Randy's Transmissions warranty terms →


Warranty claims are coordinated through Willys Workshop. Email sales@willysworkshop.com.au or call Warana (07) 5619 7869 / Oxley (07) 3377 3421 with your order number and a description of the issue.

Big purchase? Talk to our diesel team first.
Send your rego or VIN and our Australian-based team will manually confirm fitment before you buy.
Prefer to text your rego/VIN? 0485 885 957